Fruit Production and Nutrient Status in Grapefruit on Five Rootstocks

A trial was conducted during two years (2000/01 and 2001/02) on two sites using ‘Shambar’ grapefruit trees grafted to five rootstocks. The sites were located on the Greek island of Kos to evaluate the effect of rootstock and location on fruit production and leaf mineral composition of ‘Shambar’ grapefruit. Results indicated that yields were higher in 2001/02 than in 2000/01 and these differences were greater at site 2. Leaf nitrogen (N), potassium (K), zinc (Zn), and to some degree phosphorus (P) content was slightly deficient to deficient for the majority of the samples taken. Calcium (Ca) and magnesium (Mg) levels ranged from normal to high. The copper (Cu) and iron (Fe) leaf contents and the manganese (Mn) content of most samples were in the optimum range. The interactions between rootstock, site, and year upon yield and nutrient content were statistically significant. There were also significant correlation coefficients between yield and nutrient content as well as among the nutrients.     

Age, FSH Dose and Follicular Aspiration Frequency Affect Oocyte Yield from Juvenile Donor Lambs

Experiments were conducted to determine the effects of lamb age, frequency of follicular aspirations, and hormone stimulation by fixed or variable FSH dose, on the number of collected oocytes and their maturational competence. In trial 1, the characteristics of follicular population (number and diameter of follicles) were studied in 40 lambs which were slaughtered at the age of 30 days (S1), 42 days (S2), 60 days (S3) and 5–6 months (S4), each n = 10. In trial 2, 27 lambs were divided into four groups. group MF lambs (n = 6) had follicular aspiration (OPU) in four monthly intervals commencing from the age of 8–9 weeks (sessions MF1, MF2, MF3 and MF4). In groups SF2, SF3 and SF4 (each n = 6), OPU was conducted once during the 12–13, 16–17 and 20–21 week of age, respectively. Ovarian stimulation was conducted with fixed FSH dose (3.52 mg/animal). In trial 3, 10 lambs (group MV) were treated as those of group MF apart from the FSH dose, which was administered according to the body weight in a dose of 0.27 mg/kg. The number and the size of follicles, the number and the quality of collected oocytes and the maturational competence of the oocytes were compared between and within groups. In trial 1, the total number and the number of small follicles were greater in groups S1 and S2 compared with those of S3 and S4 (p < 0.01). Similarly, the follicular population was greater in group MF1 than in group SF3 (p < 0.01). In sessions MF2, MF3, MV2, MV3 and MV4, more oocytes were collected in comparison with those from the respective once‐aspirated age mates (groups SF2, SF3 and SF4). In total, more (p = 0.02) oocytes per donor were collected from group MV (15.2 ± 5.5) than from group MF (9.0 ± 3.2). An absolute maturational failure was observed in oocytes collected from groups SF2 and SF3. Maturational competence varied between 16.7% and 58.3% (p = 0.017) among sessions of group MF, but it was more uniform among sessions of group MV (range 12.5–42.9%, p > 0.05). Our results indicate that firstly, the number and the quality of harvested oocytes from juvenile lambs can be much improved if follicular stimulation regime is adjusted to the body weight. Secondly, in terms of follicular population and oocyte quality, 3 and 4‐month‐old lambs are naturally bad oocyte donors, but this characteristic can be reversed by a previous follicular ablation.     

Landscape heterogeneity enhances stability of wild bee abundance under highly varying temperature,but not under highly varying precipitation

Context

The abundance of important providers of ecosystem services such as wild bees likely increases with landscape heterogeneity, but may also fluctuate across the flowering season following varying weather conditions.

Objectives

In the present study, we investigated the combined effect of landscape heterogeneity and intra-annual variability in temperature and precipitation on the spatial and temporal stability of wild bee abundance.

Methods

We used bee monitoring data from six 4 km × 4 km sites in central Germany and 16 local communities per site. The data were collected six times per year from 2010 to 2013. Following a multimodel inference approach, we identified the importance of landscape heterogeneity, weather variability and their interaction to the stability of wild bee abundance.

Results

We found that the stability of wild bee abundance increased with landscape heterogeneity, but decreased with increasing intra-annual variability in both temperature and precipitation. However, our key finding was a buffering mechanism enabling high abundance stability in heterogeneous landscapes even under highly variable temperature conditions. Interestingly, the same mechanism did not apply for high variability in precipitation.

Conclusions

Our findings suggest that increasing landscape heterogeneity is beneficial for protecting wild bees against the projected increase in temperature variability until the end of the twenty first century, although we cannot make inferences for extreme events such as heatwaves. Nevertheless, our results equally highlight that landscape heterogeneity should not be treated as a one-size-fits-all solution and the need remains for developing alternative strategies to mitigate the effect of increasing variability in precipitation.

     

The effect of an intelligent surface drip irrigation method on sorghum biomass, energy and water savings

Over the last few decades, precipitation has decreased as a result of climate change. This change increases crop water requirements, while irrigation water is wasted because of improper irrigation scheduling. Soil moisture sensors could be used to improve irrigation scheduling and save both water and energy. The objective was to study the energy and water savings, and the gross margin achieved, when using an intelligent surface drip irrigation method on sorghum bicolor (L.) Moench. In the years 2008 and 2009, a study was conducted at the farm of the University of Thessaly, Central Greece. A Class A evaporation pan and an automated frequency domain reflectometry soil moisture sensor were used for irrigation scheduling. Two treatments in four replications were organized in a randomized complete block design: (1) pan surface drip irrigation (PSDI100) and amount of water equal to 100 % of the daily evapotranspiration (ETd), as determined by a Class A evaporation pan, and (2) automated surface drip irrigation (ASDI100) and amount of water equal to 100 % of the ETd, as determined by an automated soil moisture sensor. The mean dry biomass production and the gross margin were greater in the PSDI100 treatment. The fully automated treatment remained profitable despite the high first costs. The mean water saving was 12.5 %, while the mean energy saving was 12.4 %, and the irrigation water-use efficiency was higher in the ASDI100 treatment.     

Steroid-responsive neutropenia in a cat with progressive feline leukemia virus infection

An 8-month-old female domestic shorthair cat was presented to the Animal Medical Center with anorexia, lethargy, and mild gastrointestinal signs. A CBC revealed a profound neutropenia, and serologic testing with an in-house test kit (SNAP FIV/FeLV Combo, IDEXX) was positive for feline leukemia virus (FeLV) antigen. Serial hematologic examinations during hospitalization showed a persistent neutropenia with occasionally severe anemia and thrombocytopenia. Prednisolone administration afforded complete hematologic remission within 3 days. Four weeks after the premature discontinuation of prednisolone, the patient relapsed; however, complete and prolonged hematologic remission was achieved after prednisolone was re-induced. Bone marrow aspiration cytology was consistent with immune-mediated destruction of the mature myeloid cells. steroid-responsive (likely immune-mediated) cytopenias rarely occur in cats with progressive FeLV infection. Although only a few cases of FeLV-positive, severely neutropenic cats that responded to immunosuppressive therapy have been reported, this case highlights that a grave prognosis should not always be given to these FeLV-positive cats.     

A study on glutamate oxaloacetate transaminase isozymes of citron cultivars

For the purposes of experimental taxonomy, glutamate oxaloacetate transaminase (GOT) (EC 2.6.1.1) isozymes have been studied. The zymograms of glutamate oxaloacetate transaminase indicated the existence of three genotypes. In addition to the two loci of GOT reported (Torres et al., 1978b) a new locus was detected. Three loci composed of six alleles have been identified after PAGE gel electrophoresis of pollen extracts belonging to 7 cultivars. Two of the cultivars, 'Fimatiodes' and 'Roxani', present a genetic variation of the other five cultivars of Citrus medica L., which may indicate perhaps a separate taxonomic position.     

Estimation and Partitioning of Nitrogen Fixed by Soybean in Mediterranean Climates

A field study was conducted to estimate the nitrogen fixation by soybean [ Glycine max (L.) Merr.], using the A-value and the N-difference methods, and to examine the N partitioning within the plant. The cultivar Clark and its non-nodulating isoline (as reference crop) were grown in a silty clay (Typic Xerothent) soil, in 1991 and 1992. ₁₅N-Labelled fertilizer was surface applied in solution, at rates of 20 and 100 kg N ha⁻¹ to the nodulating and non-nodulating soybean, respectively. Plant samples were taken at full bloom (R2), beginning of seed growth (R5) and physiological maturity (R7). There was little nitrogen fixation at the early growth stages but it increased rapidly during the seed filling period. At R7 nitrogen fixed was estimated by the A-value method as 155 kg N ha_-1 in 1991 and as 240 kg N ha⁻¹ in 1992. The corresponding estimates by the N-difference method were significantly smaller. The seeds had a higher, and the vegetative parts smaller, proportion of fixed nitrogen compared to the whole plant. During the seed filling period, the translocation efficiency for fixed nitrogen was greater (93 % in 1991 and 85 % in 1992) compared to the N derived from soil (75 and 56 %, respectively). It was estimated that, after the harvest of pods, the soil was depleted by a net amount of 121 kg N ha⁻¹ in 1991 and 90 kg N ha⁻¹ in 1992.